Mini-screw Assisted Rapid Maxillary Expanders (MARME’s) have become a popular alternative to SARME in the treatment of maxillary constriction in adult patients. This study’s objective was to evaluate the effectiveness of a traditional RME appliance to achieve a successful separation of the maxillary midpalatal suture (MPS) at different ages, pubertal status, months past puberty, and gender. Additionally, we explored whether effectiveness can be improved by utilization of a mini-screw assisted RME appliance. 115 subjects (mean age of 13.6 years;​ range 7.6-29.2) were treated with two or four banded traditional RME appliances, and 25 subjects (mean age of 16.9 years;​ range 13.1-22.6) were treated with MARME’s. 73% of the traditional RME subjects and 100% of the MARME subjects had a MPS split (p= 0.001). Postpubertal patients ≥15 years of age treated with traditional RME had a 52.2% chance of achieving a MPS split, compared to 100% success rate seen with TAD RME treatment (p < 0.001). Utilizing a MARME rather than a traditional RME can greatly improve a clinician’s chances of achieving a MPS split if the patient is post-pubertal and/or ≥15 years of age.